Scroll compressor and air conditioner having the same

ABSTRACT

A scroll compressor includes a casing, a drive motor, an orbiting scroll, a fixed scroll engaged with the orbiting scroll, a back pressure chamber proximate to the orbiting scroll, an inlet pipe for supplying refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, and a discharge pipe for discharging the refrigerant discharged from the compression chamber. The scroll compressor includes an oil feed passage configured to connect the back pressure chamber and an oil storage tank provided in the casing so that oil of the oil storage tank is supplied to the back pressure chamber; and a flow control valve disposed in the oil feed passage and configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage according to a suction pressure, a discharge pressure, and a rotational velocity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Patent Application No.10-2014-0195251 filed Dec. 31, 2014 in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference inits entirety.

BACKGROUND

1. Field

The present disclosure relates to a scroll compressor used in an airconditioner. More particularly, the present disclosure relates to ascroll compressor configured so that a predetermined back pressure isapplied to the scroll compressor even when the scroll compressor isoperated at a low load during variable operation, and to an airconditioner having the same.

2. Description of the Related Art

A scroll compressor has high efficiency, low vibration, and low noise incomparison with other types of compressors, such as rotary compressors,etc., so scroll compressors have been used in various types of airconditioners. Recently, since the scroll compressor is required tooperate in accordance with an actual load in order to save energy, thescroll compressor needs to operate at a high efficiency even when theload is small.

A back pressure in a back pressure chamber of the scroll compressorgreatly influences the efficiency of the scroll compressor. The backpressure of the back pressure chamber is changed depending on operatingconditions of the air conditioner. Accordingly, in the case in which thescroll compressor is designed so that back pressure capable of axialsealing is generated at a maximum load condition, then at a low loadcondition, the back pressure is lowered so that the axial sealing of thescroll compressor is not properly performed.

In the case in which the scroll compressor is designed so that a backpressure capable of the axial sealing is generated at a minimum loadcondition, then at the maximum load condition, more back pressure thannecessary is generated so that the scroll compressor is overloaded.

SUMMARY

The present disclosure has been developed in order to overcome the abovedrawbacks and other problems associated with the conventionalarrangement. An aspect of the present disclosure relates to a scrollcompressor which can maintain constant back pressure in a back pressurechamber so as to maximize efficiency of the scroll compressor even whenan operating condition of an air conditioner in which the scrollcompressor is disposed is changed, and to an air conditioner having thesame.

Another aspect of the present disclosure relates to a scroll compressorwhich can keep an amount of oil supplied to a compression chamberconstant even when an operating condition of an air conditioner, inwhich the scroll compressor is disposed, is changed, and to an airconditioner having the same.

According to an aspect of the present disclosure, a scroll compressormay include a casing, a drive motor accommodated in the casing, anorbiting scroll to be rotated by the drive motor, a fixed scroll engagedwith the orbiting scroll, a back pressure chamber provided below theorbiting scroll, an inlet pipe that is disposed in the casing andsupplies refrigerant to a compression chamber formed by the orbitingscroll and the fixed scroll, and a discharge pipe that is disposed inthe casing and discharges the refrigerant discharged from thecompression chamber outside the casing. The scroll compressor mayinclude an oil feed passage configured to connect the back pressurechamber and an oil storage tank provided in a lower portion of thecasing so that oil of the oil storage tank is supplied to the backpressure chamber; and a flow control valve disposed in the oil feedpassage, the flow control valve configured to control an amount of oilto be supplied to the back pressure chamber via the oil feed passage,wherein the flow control valve controls the amount of oil to be suppliedvia the oil feed passage in accordance with a suction pressure of therefrigerant to be sucked through the inlet pipe, a discharge pressure ofthe refrigerant to be discharged through the discharge pipe, and arotational frequency or velocity of the drive motor.

The flow control valve may be configured to control an opening area ofthe oil feed passage.

The scroll compressor may be disposed in an outdoor unit of an airconditioner, and the flow control valve may be controlled by acontroller of the air conditioner.

The scroll compressor may include a main frame configured to support theorbiting scroll and provided with the back pressure chamber, wherein themain frame is provided with an oil feed hole connected to a dischargeend of the oil feed passage.

The oil feed hole may include a vertical hole which is connected to theback pressure chamber and is parallel to a drive shaft of the drivemotor; and a horizontal hole which is formed perpendicular to thevertical hole and is connected to the discharge end of the oil feedpassage.

When the drive motor is rotated at a low speed, the flow control valvemay increase an amount of oil passing through the oil feed passage sothat a back pressure of the back pressure chamber is a value between thesuction pressure and the discharge pressure.

When the discharge pressure of the scroll compressor is maximum, theflow control valve may cut off the oil feed passage.

According to another aspect of the present disclosure, a scrollcompressor may include a casing, a drive motor accommodated in thecasing, an orbiting scroll to be rotated by the drive motor, a fixedscroll engaged with the orbiting scroll, a back pressure chamberprovided below the orbiting scroll, an inlet pipe that is disposed inthe casing and supplies refrigerant to a compression chamber formed bythe orbiting scroll and the fixed scroll, a discharge pipe that isdisposed in the casing and discharges the refrigerant discharged fromthe compression chamber outside the casing, and an oil separator that isconnected to the discharge pipe, and separates and collects oil from thedischarged refrigerant. The scroll compressor may include an oil feedpassage configured to connect the oil separator and the back pressurechamber so that oil collected in the oil separator is supplied to theback pressure chamber; and a flow control valve disposed in the oil feedpassage, the flow control valve configured to control an amount of oilto be supplied to the back pressure chamber via the oil feed passage,wherein the flow control valve controls the amount of oil to be suppliedvia the oil feed passage in accordance with a suction pressure of therefrigerant to be sucked through the inlet pipe, a discharge pressure ofthe refrigerant to be discharged through the discharge pipe, and arotational frequency or velocity of the drive motor.

The flow control valve may be configured to control an opening area ofthe oil feed passage.

The scroll compressor may be disposed in an outdoor unit of an airconditioner, and the flow control valve may be controlled by acontroller of the air conditioner.

The scroll compressor may include a main frame configured to support theorbiting scroll and provided with the back pressure chamber, wherein themain frame is provided with an oil feed hole connected to a dischargeend of the oil feed passage.

The oil feed hole may include a vertical hole which is connected to theback pressure chamber and is parallel to a drive shaft of the drivemotor; and a horizontal hole which is formed perpendicular to thevertical hole and is connected to the discharge end of the oil feedpassage.

When the drive motor is rotated at a low speed, the flow control valvemay increase an amount of oil passing through the oil feed passage sothat a back pressure of the back pressure chamber is a value between thesuction pressure and the discharge pressure.

When the discharge pressure of the scroll compressor is maximum, theflow control valve may cut off the oil feed passage.

According to another aspect of the present disclosure, a scrollcompressor may include a casing, a drive motor accommodated in thecasing, an orbiting scroll to be rotated by the drive motor, a fixedscroll engaged with the orbiting scroll, a back pressure chamberprovided below the orbiting scroll, an inlet pipe that is disposed inthe casing and supplies refrigerant to a compression chamber formed bythe orbiting scroll and the fixed scroll, and a discharge pipe that isdisposed in the casing and discharges the refrigerant discharged fromthe compression chamber outside the casing. The scroll compressor mayinclude an oil feed passage configured to connect the compressionchamber and an oil storage tank provided in a lower portion of thecasing so that oil of the oil storage tank is supplied to thecompression chamber; and a flow control valve disposed in the oil feedpassage, the flow control valve configured to control an amount of oilto be supplied to the compression chamber via the oil feed passage,wherein the flow control valve controls the amount of oil to be suppliedvia the oil feed passage in accordance with a suction pressure of therefrigerant to be sucked through the inlet pipe, a discharge pressure ofthe refrigerant to be discharged through the discharge pipe, and arotational frequency or velocity of the drive motor.

The fixed scroll may include an auxiliary oil feed hole connecting thecompression chamber and a discharge end of the oil feed passage.

The scroll compressor may be disposed in an outdoor unit of an airconditioner, and the flow control valve may be controlled by acontroller of the air conditioner.

When the drive motor is rotated at a low speed, the flow control valvemay increase an amount of oil passing through the oil feed passage.

According to another aspect of the present disclosure, a scrollcompressor may include a casing, a drive motor accommodated in thecasing, an orbiting scroll to be rotated by the drive motor, a fixedscroll engaged with the orbiting scroll, a back pressure chamberprovided below the orbiting scroll, an inlet pipe that is disposed inthe casing and supplies refrigerant to a compression chamber formed bythe orbiting scroll and the fixed scroll, a discharge pipe that isdisposed in the casing and discharges the refrigerant discharged fromthe compression chamber outside the casing, and a vapor refrigerantinjection pipe. The scroll compressor may include an oil feed passageconfigured to connect an oil storage tank provided in a lower portion ofthe casing and the vapor refrigerant injection pipe so that oil in theoil storage tank is supplied to the compression chamber through thevapor refrigerant injection pipe; and a flow control valve disposed inthe oil feed passage, the flow control valve configured to control anamount of oil to be supplied to the vapor refrigerant injection pipe viathe oil feed passage, wherein the flow control valve controls the amountof oil to be supplied via the oil feed passage in accordance with asuction pressure of the refrigerant to be sucked through the inlet pipe,a discharge pressure of the refrigerant to be discharged through thedischarge pipe, and a rotational frequency or velocity of the drivemotor.

According to another aspect of the present disclosure, an airconditioner may include an outdoor unit in which a scroll compressorhaving at least one of the above-described features is disposed; and acontroller configured to control the scroll compressor in accordancewith set conditions.

Other aspects, advantages and salient features of the present disclosurewill become apparent from the following detailed description, which,taken in conjunction with the annexed drawings, discloses preferredembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present disclosure willbecome apparent and more readily appreciated from the followingdescription of the embodiments, taken in conjunction with theaccompanying drawings of which:

FIG. 1 is a refrigerant circuit diagram illustrating a schematicconfiguration of an air conditioner having a scroll compressor accordingto an embodiment of the present disclosure;

FIG. 2 is a cross-sectional view illustrating a scroll compressoraccording to an embodiment of the present disclosure;

FIG. 3 is a partially enlarged cross-sectional view illustrating thescroll compressor of FIG. 2;

FIG. 4 is a cross-sectional view illustrating a scroll compressoraccording to another embodiment of the present disclosure;

FIG. 5 is a cross-sectional view illustrating a scroll compressoraccording to another embodiment of the present disclosure; and

FIG. 6 is a cross-sectional view illustrating a scroll compressoraccording to another embodiment of the present disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components and structures.

DETAILED DESCRIPTION

Hereinafter, certain exemplary embodiments of the present disclosurewill be described in detail with reference to the accompanying drawings.

The matters defined herein, such as a detailed construction and elementsthereof, are provided to assist in a comprehensive understanding of thisdescription. Thus, it is apparent that exemplary embodiments may becarried out without those defined matters. Also, well-known functions orconstructions are omitted to provide a clear and concise description ofexemplary embodiments. Further, dimensions of various elements in theaccompanying drawings may be arbitrarily increased or decreased forassisting in a comprehensive understanding.

The terms used in the present application are only used to describe theexemplary embodiments, but are not intended to limit the scope of thedisclosure. The singular expression also includes the plural meaning aslong as it does not mean something different in the context. In thepresent application, the terms “include” and “consist of” designate thepresence of features, numbers, steps, operations, components, elements,or a combination thereof that are written in the specification, but donot exclude the presence or possibility of addition of one or more otherfeatures, numbers, steps, operations, components, elements, or acombination thereof.

In the exemplary embodiment of the present disclosure, a “module” or a“unit” performs at least one function or operation, and may beimplemented with hardware, software, or a combination of hardware andsoftware. In addition, a plurality of “modules” or a plurality of“units” may be integrated into at least one module except for a “module”or a “unit” which has to be implemented with specific hardware, and maybe implemented with at least one processor (not shown).

FIG. 1 is a refrigerant circuit diagram illustrating a schematicconfiguration of an air conditioner having a scroll compressor accordingto an embodiment of the present disclosure.

Referring to FIG. 1, an air conditioner 100 includes one outdoor unit110, two indoor units 120, and a controller 130. However, the airconditioner 100 according to an embodiment of the present disclosure isnot limited thereto. The number of the indoor units 120 that configuresthe air conditioner 100 as illustrated in FIG. 1 is only one example;therefore, the number of the indoor units 120 may be one or may be threeor more.

The outdoor unit 110 and the indoor units 120 are connected to eachother by pipes 121 and 122 through which refrigerant flows, therebyforming a refrigerant circuit. The two indoor units 120 are disposed inparallel in one example shown in FIG. 1.

The outdoor unit 110 is provided with a scroll compressor 1, a condenser113, and an outdoor fan 115 to supply the condenser 113 with outdoorair. Accordingly, when operating the outdoor fan 115, the outdoor air issucked into the outdoor unit 110, and then passes through the condenser113.

The indoor unit 120 is provided with an expansion valve 124, anevaporator 123, and an indoor fan 125 for supplying the evaporator 123with indoor air. Accordingly, when the indoor fan 125 is operated, theindoor air is sucked into the indoor unit 120, and then passes throughthe evaporator 123.

The controller 130 is electrically connected to the scroll compressor 1,the outdoor fan 115, and the indoor fan 125 so as to control the scrollcompressor 1, the outdoor fan 115, and the indoor fan 125. Thecontroller 130 operates the two indoor units 120 according to a user'soperation. When both of the two indoor units 120 are operated, a maximumload is applied to the scroll compressor 1 of the outdoor unit 110. Whenone of the two indoor units 120 is operated, a minimum load is appliedto the scroll compressor 1. If the air conditioner 100 includes three ormore indoor units 120 such as system air conditioners, variation in theload being applied to the scroll compressor 1 is very large.

In the scroll compressor 1 according to an embodiment of the presentdisclosure, since constant back pressure is applied to the scrollcompressor 1 even when the load varies, the sealing of a compressionchamber may be effectively performed. Accordingly, since leakage of therefrigerant from the scroll compressor 1 is prevented, operatingefficiency of the scroll compressor 1 may be improved.

Hereinafter, a scroll compressor 1 according to an embodiment of thepresent disclosure will be described in detail with reference to FIGS. 2and 3.

FIG. 2 is a cross-sectional view illustrating a scroll compressoraccording to an embodiment of the present disclosure, and FIG. 3 is apartially enlarged cross-sectional view illustrating the scrollcompressor of FIG. 2.

The scroll compressor 1 is configured to intake and compress refrigerantgas, and may include a casing 10, a main frame 20, a sub frame 30, acompression mechanism 40, a drive motor 70, an oil feed passage 80, anda flow control valve 90.

The casing 10 is formed in a cylindrical shape, and is a hermeticallysealed container in an embodiment. The casing 10 accommodates thecompression mechanism 40, the main frame 20, the sub frame 30, and thedrive motor 70 in an inner space thereof. The main frame 20 and the subframe 30 are fixed to an inside of the casing 10, and are spaced apartat a predetermined interval from each other in a vertical direction. Thedrive motor 70 is rotatably disposed between the main frame 20 and thesub frame 30.

Further, the casing 10 is provided with an inlet pipe 3 and a dischargepipe 5. The inlet pipe 3 passes through the casing 10, and one end ofthe inlet pipe 3 is connected to the compression mechanism 40. Thedischarge pipe 5 passes through the casing 10, and one end of thedischarge pipe 5 is disposed in a space between the main frame 20 andthe drive motor 70 in an inner space of the casing 10.

The compression mechanism 40 is disposed in an upper side of the mainframe 20. An oil storage tank 35, in which oil or lubricant is stored,is provided below the sub frame 30.

The main frame 20 is formed in a substantially circular plate shape, anda projecting portion 21 is formed on a bottom surface of the main frame20. The projecting portion 21 of the main frame 20 is provided with ashaft support hole 22. A bearing metal 23 is press-fitted in the shaftsupport hole 22. A main shaft portion 76 of a drive shaft 75 is insertedthrough the bearing metal 23, and the bearing metal 23 supports rotationof the drive shaft 75. A boss inserting groove 25 having an innerdiameter that is larger than an inner diameter of the shaft support hole22 is provided in the upper side of the shaft support hole 22.

An annular projection portion 26 forming a top end of the boss insertinggroove 25 is provided on a top surface of the main frame 20. The uppersurface of the annular projection portion 26 forms a mirror surface 26-1that is in contact with and supports an orbiting scroll 60. Also, an oilring 27 is disposed to surround the boss inserting groove 25 on theupper surface of the annular projection portion 26. An annular groove 28is provided around the annular projection portion 26. The annular groove28 forms a back pressure chamber. Oil supplied from the oil storage tank35 fills the back pressure chamber 28. Also, an Oldham ring 69 forpreventing rotation of the orbiting scroll 60 is disposed in the backpressure chamber 28 between the orbiting scroll 60 and the main frame20. The oil ring 27 prevents the back pressure chamber 28 from being influid communication with the boss inserting groove 25.

An oil feed hole 24 in fluid communication with the back pressurechamber 28 which is provided to support the bottom surface of theorbiting scroll 60 in the top surface of the main frame 20 is formed ina side surface of the main frame 20. The oil feed hole 24 is connectedto the oil feed passage 80 connected to the oil storage tank 35 providedin the lower portion of the casing 10. The oil feed hole 24 includes avertical hole 24-1, which is connected to the back pressure chamber 28and is parallel to a drive shaft 75 of the drive motor 70, and ahorizontal hole 24-2, which is formed substantially perpendicular to thevertical hole 24-1 and is connected to a discharge end 81 of the oilfeed passage 80.

The compression mechanism 40 includes a fixed scroll 50 and the orbitingscroll 60. The fixed scroll 50 is disposed above the main frame 20, andthe orbiting scroll 60 is disposed in a space formed by the fixed scroll50 and the main frame 20. The orbiting scroll 60 is engaged with thefixed scroll 50, is disposed between the fixed scroll 50 and the mainframe 20, and orbits with respect to the fixed scroll 50.

The fixed scroll 50 includes a body portion 51 and a plurality of fixedscroll wraps 53. The body portion 51 is formed in a certain shapecorresponding to the inner surface of the casing 10. Each of theplurality of fixed scroll wraps 53 is formed in an involute curved shapehaving predetermined thickness and height on one surface of the bodyportion 51. A discharge hole 55 is formed to pass through a center ofthe body portion 51. An inlet port 56 is formed at a side surface of thebody portion 51. The inlet port 56 is connected to the inlet pipe 3through which the refrigerant is introduced.

The orbiting scroll 60 includes a disc portion 61, a plurality oforbiting scroll wraps 63, and a boss portion 65. The disc portion 61 hascertain thickness and area. Each of the plurality of orbiting scrollwraps 63 is formed in an involute curved shape having predeterminedthickness and height on one surface of the disc portion 61. Theplurality of orbiting scroll wraps 63 are formed to be engaged with theplurality of fixed scroll wraps 53. The boss portion 65 is formed at acenter of the other side surface of the disc portion 61. The discportion 61 is provided with first oil path 66 and second oil path 67through which oil passes. The first oil path 66 is configured to connectthe boss portion 65 and the top surface of the disc portion 61. Thesecond oil path 67 is configured to connect the top surface of the discportion 61 and the side surface of the disc portion 61.

The plurality of orbiting scroll wraps 63 of the orbiting scroll 60 areengaged with the plurality of fixed scroll wraps 53 of the fixed scroll50, and the boss portion 65 is inserted in the boss inserting groove 25of the main frame 20. Also, the one surface of the disc portion 61 onwhich the boss portion 65 is formed is supported by the mirror surface26-1 of the main frame 20. Accordingly, the one surface of the discportion 61 being supported by the mirror surface 26-1 of the main frame20 also is formed as a mirror surface 61-1.

Compression pockets P formed by the plurality of fixed scroll wraps 53of the fixed scroll 50 and the plurality of orbiting scroll wraps 63 ofthe orbiting scroll 60 configure a compression chamber.

The drive motor 70 includes a stator 71 and a rotor 72. The stator 71 isfixed to the inner surface of the casing 10. The rotor 72 is rotatablyinserted inside the stator 71. Also, the drive shaft 75 is insertedthrough the rotor 72.

The drive shaft 75 includes a shaft portion 76 having a predeterminedlength and an eccentric portion 77 extending from one end of the shaftportion 76. The shaft portion 76 of the drive shaft 75 is press-fittedin the rotor 72 of the drive motor 70. The one end of the shaft portion76 is inserted in the projecting portion 21 of the main frame 20 and issupported by the bearing metal 23. The eccentric portion 77 of the driveshaft 75 is inserted in the boss portion 65 of the orbiting scroll 60. Abearing metal 64 is disposed between the eccentric portion 77 of thedrive shaft 75 and the boss portion 65 of the orbiting scroll 60.

A balance weight 74 is disposed in the shaft portion 76 of the driveshaft 75 above the rotor 72. The lower portion of the shaft portion 76is supported by a bearing metal 31 disposed in the sub frame 30.

Also, the drive shaft 75 is provided with an oil-passage 78 formed topenetrate the shaft portion 76 and the eccentric portion 77. A bottomend 37 of the drive shaft 75 is submerged in the oil storage tank 35 ofthe casing 10. When the drive shaft 75 is rotated, oil stored in the oilstorage tank 35 is supplied to the boss portion 65 of the orbitingscroll 60 via the oil passage 78 of the drive shaft 75 by pressure beingapplied to the oil storage tank 35.

The oil feed passage 80 is configured to connect the oil storage tank 35provided in the lower portion of the casing 10 and the back pressurechamber 28 provided in the main frame 20. Accordingly, a discharge end81 of the oil feed passage 80 is connected to the oil feed hole 24formed in the main frame 20. The oil being received in the oil storagetank 35 is supplied to the back pressure chamber 28 via the oil feedpassage 80 by the pressure being applied to the oil storage tank 35. Theoil feed passage 80 may be formed of a pipe or a tube.

The flow control valve 90 is disposed in the oil feed passage 80, andadjusts an amount of the oil that passes through the oil feed passage 80and moves to the back pressure chamber 28. The flow control valve 90 maybe configured to adjust the amount of the oil passing through the oilfeed passage 80 by controlling an opening area of the oil feed passage80. The flow control valve 90 may use an electronic proportionalsolenoid valve that can adjust the opening area in accordance withelectric signals. The flow control valve 90 may be configured to controlthe amount of the oil supplied via the oil feed passage 80 in accordancewith a suction pressure of the refrigerant being sucked through theinlet pipe 3 of the casing 10, a discharge pressure of the refrigerantbeing discharged through the discharge pipe 5 of the casing 10, and arotational frequency or velocity of the drive motor 70.

In the present embodiment in which the scroll compressor 1 is disposedin the air conditioner 100 (see FIG. 1), the flow control valve 90 iselectrically connected to a controller 130 of the air conditioner 100 sothat the flow control valve 90 is controlled by the controller 130. Indetail, the controller 130 of the air conditioner 100 measures inreal-time the suction pressure of the refrigerant being sucked throughthe inlet pipe 3 of the scroll compressor 1, the discharge pressure ofthe refrigerant being discharged through the discharge pipe 5 of thescroll compressor 1, and the rotational frequency or velocity of thedrive motor 70, and controls the flow control valve 90 to supply anamount of oil that can apply a suitable pressure to the back pressurechamber 28 of the main frame 20 depending on the measured suctionpressure, discharge pressure, and rotational frequency or velocity.Opening degrees of the flow control valve 90 depending on the suctionpressure and discharge pressure of the refrigerant and the rotationalfrequency or velocity of the drive motor 70 may be stored in a memory ofthe controller 130 as a look-up table.

Hereinafter, operation of the scroll compressor 1 according to anembodiment of the present disclosure having the above-describedstructure will be described with reference to FIGS. 2 and 3.

First, when the power of the scroll compressor 1 is turned on, the poweris applied to the drive motor 70 so that the rotor 72 of the drive motor70 is rotated. When the rotor 72 of the drive motor 70 rotates, thedrive shaft 75 integrally connected to the rotor 72 is rotated andsupported by the bearing metal 23 of the main frame 20 and the bearingmetal 31 of the sub frame 30. When the drive shaft 75 is rotated, theorbiting scroll 60 connected to the eccentric portion 77 of the driveshaft 75 orbits based on a shaft center of the drive shaft 75. At thistime, the orbiting scroll 60 is prevented from rotating by an Oldhamring, and performs an orbiting motion.

When the orbiting scroll 60 is orbited by the drive shaft 75, theplurality of orbiting scroll wraps 63 of the orbiting scroll 60 areorbited while being engaged with the plurality of fixed scroll wraps 53of the fixed scroll 50. Thus, the plurality of compression pockets P areformed by the plurality of orbiting scroll wraps 63 and the plurality offixed scroll wraps 53. As the plurality of compression pockets P changein volume while moving toward the center of the fixed scroll 50 and theorbiting scroll 60, the compression pockets P suck refrigerant, compressthe sucked refrigerant, and then discharge the compressed refrigerantthrough a discharge hole 55 of the fixed scroll 50. The refrigerantdischarged through the discharge hole 55 enters the discharge pipe 5disposed in a side wall of the casing 10 via the inner space of thecasing 10, and is discharged outside the casing 10 through the dischargepipe 5. The refrigerant being introduced into the compression pockets Pformed by the plurality of fixed scroll wraps 53 and orbiting scrollwraps 63 is sucked through the inlet port 56 that is formed in the sidesurface of the main frame 20 and is connected to the inlet pipe 3.

When the drive shaft 75 is rotated, the oil stored in the oil storagetank 35 of the lower portion of the casing 10 is supplied toward a topend of the drive shaft 75 through the oil passage 78 formed inside thedrive shaft 75 the bottom end of which is submerged in the oil storagetank 35 by the pressure acting on the inside of the casing 10. The oilbeing supplied through the oil passage 78 formed in the drive shaft 75fills the boss portion 65 of the orbiting scroll 60, and then fills theboss inserting groove 25 of the main frame 20 via the bearing metal 64of the boss portion 65.

Some of the oil filling the boss portion 65 is supplied to the topsurface of the orbiting scroll 60 via the first oil path 66 provided inthe disc portion 61 of the orbiting scroll 60. The oil supplied to thetop surface of the orbiting scroll 60 via the first oil path 66 isintroduced between the plurality of fixed scroll wraps 53 of the fixedscroll 50 and the plurality of orbiting scroll wraps 63 of the orbitingscroll 60 so that the oil performs a sealing function to prevent leakageof the refrigerant as well as a lubrication function to prevent frictionbetween the contact surfaces between the top end surfaces of theplurality of orbiting scroll wraps 63 and a contacting surface of thefixed scroll 50 in contact with the top end surfaces of the orbitingscroll wraps 63 and between the bottom end surfaces of the plurality offixed scroll wraps 53 of the fixed scroll 50 and a contacting surface ofthe orbiting scroll 60 in contact with the bottom end surfaces of theplurality of fixed scroll 50.

Further, some of the oil supplied between the fixed scroll 50 and theorbiting scroll 60 is discharged through the side surface of the discportion 61 of the orbiting scroll 60 via the second oil path 67, andthen is supplied to the back pressure chamber 28. The oil supplied tothe back pressure chamber 28 may press the orbiting scroll 60 upwardlyso that the orbiting scroll 60 is orbited with respect to the fixedscroll 50 in a sealed state.

On the other hand, some of the oil filled in the boss inserting groove25 is supplied between the mirror surface 61-1 of the disc portion 61 ofthe orbiting scroll 60 and the mirror surface 26-1 of the main frame 20.Also, some of the oil filled in the boss inserting groove 25 is returnedto the oil storage tank 35 provided in the lower portion of the casing10 via the bearing metal 23 disposed in the projecting portion 21 of themain frame 20.

Further, some of the oil supplied to the top end of the drive shaft 75via the oil passage 78 of the drive shaft 75 is directly supplied to thebearing metal 23 disposed in the projecting portion 21 of the main frame20 via an auxiliary oil passage 79 provided in the shaft portion 76 ofthe drive shaft 75.

When the scroll compressor 1 is disposed in the air conditioner 100 (seeFIG. 1), the capacity of the scroll compressor 1 is varied in accordancewith the load acting on the air conditioner 100. In other words, if theload becomes larger, the scroll compressor 1 increases the capacity forcompressing the refrigerant by increasing the operation speed of thescroll compressor 1. When the load becomes smaller, the scrollcompressor 1 decreases the capacity for compressing the refrigerant byreducing the operation speed of the scroll compressor 1.

When the operation speed of the scroll compressor 1 is taken at a highspeed in order to increase the capacity of the scroll compressor 1,high-pressure is applied to the oil storage tank 35 so that a largeamount of oil is supplied to the boss portion 65 via the oil passage 78of the drive shaft 75. Therefore, the sufficient amount of oil issupplied between the plurality of orbiting scroll wraps 63 and theplurality of fixed scroll wraps 53 through the first oil path 66 of thedisc portion 61 of the orbiting scroll 60, and the amount of oil beingsupplied to the back pressure chamber 28 via the first oil path 66 andthe second oil path 67 becomes sufficient so that a proper back pressureis applied to the back pressure chamber 28, and thus the sealing of thecompression chamber P is effectively performed. Accordingly, in thiscase, the flow control valve 90 blocks the oil, which is stored in theoil storage tank 35 of the casing 10, from being supplied to the backpressure chamber 28 via the oil feed passage 80 by cutting off the oilfeed passage 80. For example, when the scroll compressor 1 rotates at amaximum speed, the flow control valve 90 may cut off the oil feedpassage 80 so that the oil stored in the oil storage tank 35 of thecasing 10 is not supplied to the back pressure chamber 28 via the oilfeed passage 80.

However, when the operation speed of the scroll compressor 1 is at a lowspeed since the load of the air conditioner 100 (see FIG. 1) is small,low-pressure is applied to the oil storage tank 35 so that the amount ofoil being supplied to the boss portion 65 of the orbiting scroll 60 viathe oil passage 78 of the drive shaft 75 becomes small. Therefore, theamount of oil being supplied between the plurality of orbiting scrollwraps 63 and the plurality of fixed scroll wraps 53 through the firstoil path 66 of the disc portion 61 of the orbiting scroll 60 isdecreased, and in particular, the amount of oil being supplied to theback pressure chamber 28 via the first oil path 66 and the second oilpath 67 is rapidly reduced.

As described above, when the amount of oil being supplied via the oilpassage 78 of the drive shaft 75 is small due to the low operation speedof the scroll compressor 1, in the scroll compressor 1 according to anembodiment of the present disclosure, the oil accommodated in the oilstorage tank 35 of the casing 10 is supplied to the back pressurechamber 28 of the main frame 20 via the oil feed passage 80. At thistime, the flow control valve 90 controls properly the amount of oilpassing through the oil feed passage 80 in accordance with the suctionpressure of the refrigerant being sucked into the scroll compressor 1,the discharge pressure of the refrigerant being discharged from thescroll compressor 1, and the rotational frequency or velocity of thedrive motor 70. Accordingly, in the scroll compressor 1 according to anembodiment of the present disclosure, even when the scroll compressor 1is rotated at a low speed, the oil stored in the oil storage tank 35 ofthe casing 10 is supplied to the back pressure chamber 28 via the oilfeed passage 80 disposed in the outside of the casing 10 as well as viathe oil passage 78 of the drive shaft 75 so that a proper back pressureis generated in the back pressure chamber 28. In other words, the oil ofthe oil storage tank 35 may be supplied to the back pressure chamber 28via the oil feed passage 80 so that the back pressure in the backpressure chamber 28 becomes a value between the suction pressure and thedischarge pressure of the refrigerant.

For example, when a ratio of the discharge pressure Pd to the suctionpressure Ps is 2 or less, namely, Pd/Ps≦2, and the rotational frequencyor velocity is 30 revolutions per second (RPS) or less, namely, RPS≦30,the controller 130 may be set to open the flow control valve 90 so thatthe oil in the oil storage tank 35 is supplied to the back pressurechamber 28 through the oil feed passage 80.

Accordingly, in the scroll compressor 1 according to an embodiment ofthe present disclosure having the structure as described above, when thescroll compressor 1 is rotated at a high speed due to the high load ofthe scroll compressor 1 so that a high pressure is applied to the insideof the casing 10, the oil is sufficiently supplied to the back pressurechamber 28 via the oil passage 78 of the drive shaft 75 so that thecompression chamber P formed by the fixed scroll 50 and the orbitingscroll 60 is effectively sealed. Also, when the scroll compressor 1 isrotated at a low speed due to the low load of the scroll compressor 1 sothat a low pressure is applied to the inside of the casing 10, the oilof the oil storage tank 35 is directly supplied to the back pressurechamber 28 via the oil feed passage 80 disposed outside the casing 10 inaddition to the oil passage 78 of the drive shaft 75 so that a properback pressure is applied to the back pressure chamber 28. As a result,the compression chamber P formed by the fixed scroll 50 and the orbitingscroll 60 is effectively sealed. Accordingly, even if the size of theload acting on the air conditioner 100 varies, the scroll compressor 1according to an embodiment of the present disclosure may be operated ata high efficiency.

Hereinafter, a scroll compressor according to another embodiment of thepresent disclosure will be described with reference to FIG. 4.

FIG. 4 is a cross-sectional view illustrating a scroll compressoraccording to another embodiment of the present disclosure.

Referring to FIG. 4, a scroll compressor 1′ according to an embodimentof the present disclosure may include a casing 10, a main frame 20, asub frame 30, a compression mechanism 40, a drive motor 70, an oil feedpassage 80′, and a flow control valve 90.

The casing 10, the main frame 20, the sub frame 30, the compressionmechanism 40, and the drive motor 70 are the same as those of the scrollcompressor 1 according to the above-described embodiment; therefore,detailed descriptions thereof will be omitted.

The scroll compressor 1′ according to the present embodiment isdifferent from the scroll compressor 1 according to the above-describedembodiment in that oil separated by an oil separator 200 is supplied tothe back pressure chamber 28 instead of oil of the oil storage tank 35of the casing 10.

Accordingly, the oil separator 200 for separating oil from therefrigerant discharged from the scroll compressor 1′ is disposed in oneside of the scroll compressor 1′ according to an embodiment of thepresent disclosure. An inlet 201 to which the discharge pipe 5 of thescroll compressor 1′ is connected is provided in a side surface of theoil separator 200. A refrigerant discharge pipe 203 is connected to atop end of the oil separator 200, and an oil return pipe 205 is providedat a bottom end of the oil separator 200. The refrigerant containing oilis introduced into the oil separator 200 through the inlet 201, and theoil is separated from the refrigerant by the oil separator 200. Therefrigerant from which the oil has been removed is supplied to thecondenser 113 (see FIG. 1) through the refrigerant discharge pipe 203,and the separated oil is discharged through the oil return pipe 205.

The oil feed passage 80′ is configured to connect the oil return pipe205 of the oil separator 200 and the back pressure chamber 28 of thecasing 10. Accordingly, the main frame 20 of the scroll compressor 1′ isprovided with an oil feed hole 24 which is connected to a discharge end81 of the oil feed passage 80′. The oil feed hole 24 includes a verticalhole 24-1, which is connected to the back pressure chamber 28 and isparallel to the drive shaft 75 of the drive motor 70, and a horizontalhole 24-2, which is formed substantially perpendicular to the verticalhole 24-1 and is connected to the discharge end 81 of the oil feedpassage 80′. Accordingly, the oil separated in the oil separator 200 maybe supplied to the back pressure chamber 28 through the oil feed passage80′ connecting the oil separator 200 and the back pressure chamber 28 ofthe scroll compressor 1′. At this time, the oil separated in the oilseparator 200 is supplied to the back pressure chamber 28 by thedifference in pressure acting on the oil separator 200 and the backpressure chamber 28.

Also, the oil feed passage 80′ is provided with a flow control valve 90to control the amount of oil that passes through the oil feed passage80′ and moves to the back pressure chamber 28. The flow control valve 90may be configured to adjust the amount of the oil passing through theoil feed passage 80′ by controlling an opening area of the oil feedpassage 80′. The flow control valve 90 may use an electronicproportional solenoid valve that can adjust the opening area inaccordance with electric signals. The flow control valve 90 may beconfigured to control the amount of the oil supplied via the oil feedpassage 80′ in accordance with the suction pressure of the refrigerantbeing sucked through the inlet pipe 3 of the casing 10, the dischargepressure of the refrigerant being discharged through the discharge pipe5 of the casing 10, and the rotational frequency or velocity of thedrive motor 70. The flow control valve 90 is the same as the flowcontrol valve 90 of the scroll compressor 1 according to theabove-described embodiment; therefore, a detailed description thereofwill be omitted.

In the scroll compressor 1′ according to an embodiment of the presentdisclosure having the above-described structure, when the scrollcompressor 1′ is rotated at a high speed because a high load is appliedto the air conditioner 100, the oil is sufficiently supplied to thecompression chamber P formed by the fixed scroll 50 and the orbitingscroll 60 and the back pressure chamber 28 formed by the orbiting scroll60 and the main frame 20 via the oil passage 78 of the drive shaft 75 inthe same as the scroll compressor 1 according to the above-describedembodiment. Accordingly, the scroll compressor 1′ may efficientlycompress and discharge the refrigerant being sucked. At this time, theflow control valve 90 blocks the oil collected by the oil separator 200from being supplied to the back pressure chamber 28 by cutting off theoil feed passage 80′.

However, when the scroll compressor 1′ is rotated at a low speed since alow load is applied to the air conditioner 100, the amount of oil beingsupplied to the compression chamber P formed by the fixed scroll 50 andthe orbiting scroll 60 and the back pressure chamber 28 formed by theorbiting scroll 60 and the main frame 20 via the oil passage 78 of thedrive shaft 75 is reduced. In this case, the flow control valve 90properly controls the amount of oil being supplied to the back pressurechamber 28 in accordance with the load being applied to the scrollcompressor 1′.

In detail, the flow control valve 90 properly controls the amount of theoil that passes through the oil feed passage 80′ and is supplied to theback pressure chamber 28 in accordance with the suction pressure of therefrigerant being sucked into the scroll compressor 1′, the dischargepressure of the refrigerant being discharged from the scroll compressor1′, and the rotational frequency or velocity of the drive motor 70. Atthis time, the flow control valve 90 may be controlled by the controller130 of the air conditioner 100. Accordingly, in the scroll compressor 1′according to an embodiment of the present disclosure, even when thescroll compressor 1′ is rotated at a low speed, the oil collected by theoil separator 200 is supplied to the back pressure chamber 28 via theoil feed passage 80′ connected to the oil separator 200 that is disposedin the outside of the casing 10 as well as the oil passage 78 of thedrive shaft 75 so that a proper pressure is generated in the backpressure chamber 28.

Accordingly, in the scroll compressor 1′ according to an embodiment ofthe present disclosure having the structure as described above, when thescroll compressor 1′ is rotated at a high speed due to the high load ofthe scroll compressor 1, the oil is sufficiently supplied to the backpressure chamber 28 via the oil passage 78 of the drive shaft 75 so thatthe compression chamber P formed by the fixed scroll 50 and the orbitingscroll 60 is effectively sealed. Also, when the scroll compressor 1′ isrotated at a low speed since a low load acts on the scroll compressor1′, the oil separated in the oil separator 200 is directly supplied tothe back pressure chamber 28 via the oil feed passage 80′ disposedoutside the casing 10 in addition to the oil passage 78 of the driveshaft 75 so that the compression chambers P formed by the fixed scroll50 and the orbiting scroll 60 are effectively sealed. Accordingly, evenif the size of the load acting on the air conditioner 100 varies, thescroll compressor 1′ according to an embodiment of the presentdisclosure may be operated at a high efficiency.

Hereinafter, a scroll compressor according to another embodiment of thepresent disclosure will be described with reference to FIG. 5.

FIG. 5 is a cross-sectional view illustrating a scroll compressoraccording to another embodiment of the present disclosure.

Referring to FIG. 5, a scroll compressor 2 according to an embodiment ofthe present disclosure may include a casing 10, a main frame 20′, a subframe 30, a compression mechanism 40, a drive motor 70, an oil feedpassage 80″, and a flow control valve 90.

The casing 10, the sub frame 30, the compression mechanism 40, and thedrive motor 70 are the same as those of the scroll compressor 1according to the above-described embodiment; therefore, detaileddescriptions thereof will be omitted. However, the main frame 20′ has astructure similar to that of the scroll compressor 1 as described above,but is different from the main frame 20 of the scroll compressor 1according to the above described embodiment in that the main frame 20′is not provided with the oil feed hole 24.

The scroll compressor 2 according to the present embodiment is differentfrom the scroll compressor 1 according to the above-described embodimentin the structure in which the oil of the oil storage tank 35 of thecasing 10 is supplied to not the back pressure chamber 28 but thecompression chamber P.

Accordingly, the scroll compressor 2 according to the present embodimentincludes an oil feed passage 80″ that is provided in the outside of thecasing 10 and connects the oil storage tank 35 of the casing 10 and thecompression chamber P formed by the fixed scroll 50′ and the orbitingscroll 60. An auxiliary oil feed hole 54 is formed in a side surface ofthe fixed scroll 50′ in order to connect the oil feed passage 80″ andthe compression chamber P. The auxiliary oil feed hole 54 is formed sothat the side surface of the body portion 51 of the fixed scroll 50′ isin fluid communication with the bottom surface of the body portion 51 onwhich the plurality of fixed scroll wraps 53 are not formed. In detail,the auxiliary oil feed hole 54 includes a horizontal hole 54-1 which isformed at the side surface of the body portion 51 and parallel to bodyportion 51 and a vertical hole 54-2 which is formed substantiallyperpendicular to the horizontal hole 54-1 and is formed to meet thehorizontal hole 54-1 in a surface of the body portion 51 between theplurality of fixed scroll wraps 53. At this time, the vertical hole 54-2may be disposed adjacent to the fixed scroll wrap 53 which is locatedoutermost.

A discharge end 81 of the oil feed passage 80″ is connected to thehorizontal hole 54-1 of the auxiliary oil feed hole 54. Accordingly, theoil stored in the oil storage tank 35 of the casing 10 may be suppliedto the compression chamber P formed by the fixed scroll wraps 53 and theorbiting scroll wraps 63 through the oil feed passage 80″ and theauxiliary oil feed hole 54.

Also, a flow control valve 90 is provided in the oil feed passage 80″ tocontrol the amount of oil that passes through the oil feed passage 80″and is supplied to the compression chamber P. The flow control valve 90may be configured to adjust the amount of the oil passing through theoil feed passage 80″ by controlling an opening area of the oil feedpassage 80″. The flow control valve 90 may use an electronicproportional solenoid valve that can adjust the opening area inaccordance with electric signals. The flow control valve 90 may beconfigured to control the amount of the oil supplied via the oil feedpassage 80″ in accordance with the suction pressure of the refrigerantbeing sucked through the inlet pipe 3 of the casing 10, the dischargepressure of the refrigerant being discharged through the discharge pipe5 of the casing 10, and the rotational frequency or velocity of thedrive motor 70. The flow control valve 90 is the same as the flowcontrol valve 90 of the scroll compressor 1 according to theabove-described embodiment; therefore, a detailed description thereofwill be omitted.

In the scroll compressor 2 according to an embodiment of the presentdisclosure having the above-described structure, when the scrollcompressor 2 is rotated at a high speed because a high load is appliedto the air conditioner 100, the oil is sufficiently supplied to thecompression chamber P formed by the fixed scroll 50′ and the orbitingscroll 60 via the oil passage 78 of the drive shaft 75 and the first oilpath 66 of the orbiting scroll 60 in the same as the scroll compressor 1according to the above-described embodiment. Also, some of the oilsupplied to the compression chamber P may be supplied to the backpressure chamber 28 via the second oil path 67 provided in the orbitingscroll 60. Accordingly, the scroll compressor 2 may efficiently compressand discharge the refrigerant being sucked. At this time, the flowcontrol valve 90 blocks the oil stored in the oil storage tank 35 of thecasing 10 from being supplied to the compression chamber P by cuttingoff the oil feed passage 80″.

However, when the scroll compressor 2 is rotated at a low speed since alow load is applied to the air conditioner 100 (see FIG. 1), the amountof oil being supplied to the compression chamber P formed by the fixedscroll 50 and the orbiting scroll 60 via the oil passage 78 of the driveshaft 75 is reduced. In this case, the flow control valve 90 properlycontrols the amount of oil being supplied to the compression chamber Pvia the oil feed passage 80″ in accordance with the load being appliedto the scroll compressor 2.

In detail, the flow control valve 90 properly controls the amount of theoil that passes through the oil feed passage 80″ and is supplied to thecompression chamber P in accordance with the suction pressure of therefrigerant being sucked into the scroll compressor 2, the dischargepressure of the refrigerant being discharged from the scroll compressor2, and the rotational frequency or velocity of the drive motor 70. Atthis time, the flow control valve 90 may be controlled by the controller130 of the air conditioner 100. Accordingly, in the scroll compressor 2according to an embodiment of the present disclosure, even when thescroll compressor 2 is rotated at a low speed, the oil of the oilstorage tank 35 is supplied to the compression chamber P via the oilfeed passage 80″ that is disposed in the outside of the casing 10 and isconnected to the oil storage tank 35 as well as the oil passage 78 ofthe drive shaft 75 so that the compression chamber P is sufficientlysealed. Also, the oil is supplied to the back pressure chamber 28through the second oil path 67 of the orbiting scroll 60 so that aproper back pressure is generated in the back pressure chamber 28.

Accordingly, in the scroll compressor 2 according to an embodiment ofthe present disclosure having the structure as described above, when thescroll compressor 2 is rotated at a high speed since the high load isapplied to the scroll compressor 2, the oil is sufficiently supplied tothe compression chamber P and the back pressure chamber 28 via the oilpassage 78 of the drive shaft 75 so that the compression chamber Pformed by the fixed scroll 50′ and the orbiting scroll 60 is effectivelysealed. Also, when the scroll compressor 2 is rotated at a low speedsince a low load is applied to the scroll compressor 2, the oil of theoil storage tank 35 of the casing 10 is directly supplied to thecompression chamber P via the oil feed passage 80″ disposed outside thecasing 10 in addition to the oil passage 78 of the drive shaft 75 sothat the compression chamber P formed by the fixed scroll 50′ and theorbiting scroll 60 is effectively sealed. Accordingly, even if the sizeof the load acting on the air conditioner 100 varies, the scrollcompressor 2 according to an embodiment of the present disclosure may beoperated at a high efficiency.

Hereinafter, a scroll compressor according to another embodiment of thepresent disclosure will be described with reference to FIG. 6.

FIG. 6 is a cross-sectional view illustrating a scroll compressoraccording to another embodiment of the present disclosure.

Referring to FIG. 6, a scroll compressor 2′ according to an embodimentof the present disclosure may include a casing 10, a main frame 20′, asub frame 30, a compression mechanism 40, a drive motor 70, an oil feedpassage 80′, and a flow control valve 90.

The casing 10, the main frame 20′, the sub frame 30, the compressionmechanism 40, and the drive motor 70 are the same as those of the scrollcompressor 2 according to the above-described embodiment; therefore,detailed descriptions thereof will be omitted.

The scroll compressor 2′ according to the present embodiment isdifferent from the scroll compressor 2 according to the above-describedembodiment in that it further includes a vapor refrigerant injectionpipe 300 for supplying refrigerant to the compression chamber P formedby the fixed scroll 50′ and the orbiting scroll 60.

Accordingly, a refrigerant injection hole 57 is provided in the one sidesurface of the fixed scroll 50′. The refrigerant injection hole 57 isformed so that the one side surface of the body portion 51 of the fixedscroll 50′ is in fluid communication with a portion of the bottomsurface of the body portion 51 on which the plurality of fixed scrollwraps 53 are not formed. In detail, the refrigerant injection hole 57includes a horizontal hole 57-1 which is formed at the one side surfaceof the body portion 51 and parallel to body portion 51 and a verticalhole 57-2 which is formed substantially perpendicular to the horizontalhole 57-1 and is formed to meet the horizontal hole 57-1 in a portion ofthe bottom surface of the body portion 51 between the plurality of fixedscroll wraps 53. At this time, the vertical hole 57-2 may be disposed ata portion of the bottom surface of the body portion 51 adjacent to thefixed scroll wrap 53 which is located outermost. The vapor refrigerantinjection pipe 300 is connected to the horizontal hole 57-1 of therefrigerant injection hole 57.

The oil feed passage 80′″ of the scroll compressor 2′ according to thepresent embodiment is disposed to connect the vapor refrigerantinjection pipe 300 and the oil storage tank 35 of the casing 10 in theoutside of the casing 10. A discharge end 81 of the oil feed passage80′″ is connected to the vapor refrigerant injection pipe 300.Accordingly, the oil stored in the oil storage tank 35 of the casing 10is supplied to the vapor refrigerant injection pipe 300 through the oilfeed passage 80′″, and then is supplied to the compression chamber Pformed by the fixed scroll 50 and the orbiting scroll 60 along with therefrigerant being introduced into the vapor refrigerant injection pipe300.

Also, a flow control valve 90 is provided in the oil feed passage 80′″to control the amount of oil that passes through the oil feed passage80′ and is supplied to the vapor refrigerant injection pipe 300. Theflow control valve 90 may be configured to adjust the amount of the oilpassing through the oil feed passage 80′″ by controlling an opening areaof the oil feed passage 80′″. The flow control valve 90 may use anelectronic proportional solenoid valve that can adjust the opening areain accordance with electric signals. The flow control valve 90 may beconfigured to control the amount of the oil supplied via the oil feedpassage 80′″ in accordance with the suction pressure of the refrigerantbeing sucked through the inlet pipe 3 of the casing 10, the dischargepressure of the refrigerant being discharged through the discharge pipe5 of the casing 10, and the rotational frequency or velocity of thedrive motor 70. The flow control valve 90 is the same as the flowcontrol valve 90 of the scroll compressor 1 according to theabove-described embodiment; therefore, a detailed description thereofwill be omitted.

In the scroll compressor 2′ according to an embodiment of the presentdisclosure having the above-described structure, when the scrollcompressor 2′ is rotated at a high speed because a high load is appliedto the air conditioner 100, the oil is sufficiently supplied to thecompression chamber P formed by the fixed scroll 50′ and the orbitingscroll 60 via the oil passage 78 of the drive shaft 75 and the first oilpath 66 of the orbiting scroll 60 in the same as the scroll compressor 1according to the above-described embodiment. Also, some of the oilsupplied to the compression chamber P may be supplied to the backpressure chamber 28 via the second oil path 67 provided in the orbitingscroll 60. Accordingly, the scroll compressor 2′ may efficientlycompress and discharge the refrigerant being sucked. At this time, theflow control valve 90 blocks the oil stored in the oil storage tank 35of the casing 10 from being supplied to the compression chamber P viathe vapor refrigerant injection pipe 300 by cutting off the oil feedpassage 80′″. Accordingly, only vapor refrigerant is supplied to thecompression chamber P through the vapor refrigerant injection pipe 300.

However, when the scroll compressor 2′ is rotated at a low speed since alow load is applied to the air conditioner 100, the amount of oil beingsupplied to the compression chamber P formed by the fixed scroll 50′ andthe orbiting scroll 60 via the oil passage 78 of the drive shaft 75 isreduced. In this case, the flow control valve 90 properly controls theamount of oil being supplied to the vapor refrigerant injection pipe 300via the oil feed passage 80′″ in accordance with the load being appliedto the scroll compressor 2′.

In detail, the flow control valve 90 properly controls the amount of theoil that passes through the oil feed passage 80′″ and is supplied to thevapor refrigerant injection pipe 300 in accordance with the suctionpressure of the refrigerant being sucked into the scroll compressor 2′,the discharge pressure of the refrigerant being discharged from thescroll compressor 2, and the rotational frequency or velocity of thedrive motor 70. At this time, the flow control valve 90 may becontrolled by the controller 130 of the air conditioner 100.Accordingly, in the scroll compressor 2′ according to an embodiment ofthe present disclosure, even when the scroll compressor 2′ is rotated ata low speed, the oil of the oil storage tank 35 is supplied to the vaporrefrigerant injection pipe 300 via the oil feed passage 80′″, which isdisposed in the outside of the casing 10 and is connected to the oilstorage tank 35, and then is supplied to the compression chamber Ptogether with the refrigerant through the vapor refrigerant injectionpipe 300 as well as the oil passage 78 of the drive shaft 75 so that thecompression chamber P is sufficiently sealed. Also, some of the oil inthe compression chamber P is supplied to the back pressure chamber 28through the second oil path 67 of the orbiting scroll 60 so that aproper back pressure is generated in the back pressure chamber 28.

Accordingly, in the scroll compressor 2′ according to an embodiment ofthe present disclosure having the structure as described above, when thescroll compressor 2′ is rotated at a high speed since a high load isapplied to the scroll compressor 2′, the oil is sufficiently supplied tothe compression chamber P and the back pressure chamber 28 via the oilpassage 78 of the drive shaft 75 so that the compression chamber Pformed by the fixed scroll 50′ and the orbiting scroll 60 is effectivelysealed. Also, when the scroll compressor 2′ is rotated at a low speedsince a low load is applied to the scroll compressor 2′, the oil of theoil storage tank 35 of the casing 10 is directly supplied to thecompression chamber P with the refrigerant via the oil feed passage 80′″and the vapor refrigerant injection pipe 300 disposed outside the casing10 in addition to the oil passage 78 of the drive shaft 75 so that thecompression chamber P formed by the fixed scroll 50′ and the orbitingscroll 60 is effectively sealed. Accordingly, even if the size of theload acting on the air conditioner 100 varies, the scroll compressor 2′according to an embodiment of the present disclosure may be operated ata high efficiency.

While the embodiments of the present disclosure have been described,additional variations and modifications of the embodiments may occur tothose skilled in the art once they learn of the basic inventiveconcepts. Therefore, it is intended that the appended claims shall beconstrued to include both the above embodiments and all such variationsand modifications that fall within the spirit and scope of the inventiveconcepts.

What is claimed is:
 1. A scroll compressor which comprises a casing, adrive motor accommodated in the casing, an orbiting scroll to be rotatedby the drive motor, a fixed scroll engaged with the orbiting scroll, aback pressure chamber provided proximate to the orbiting scroll, aninlet pipe that is disposed in the casing and supplies refrigerant to acompression chamber formed by the orbiting scroll and the fixed scroll,and a discharge pipe that is disposed in the casing and discharges therefrigerant discharged from the compression chamber outside the casing,the scroll compressor comprising: an oil feed passage configured toconnect the back pressure chamber and an oil storage tank provided inthe casing so that oil of the oil storage tank is supplied to the backpressure chamber; and a flow control valve disposed in the oil feedpassage, the flow control valve configured to control an amount of oilto be supplied to the back pressure chamber via the oil feed passage,wherein the flow control valve controls the amount of oil to be suppliedvia the oil feed passage in accordance with a suction pressure of therefrigerant to be sucked through the inlet pipe, a discharge pressure ofthe refrigerant to be discharged through the discharge pipe, and arotational velocity of the drive motor.
 2. The scroll compressor ofclaim 1, wherein the flow control valve is configured to control anopening area of the oil feed passage.
 3. The scroll compressor of claim1, wherein the scroll compressor is disposed in an outdoor unit of anair conditioner, and the flow control valve is controlled by acontroller of the air conditioner.
 4. The scroll compressor of claim 1,further comprising: a main frame configured to support the orbitingscroll and provided with the back pressure chamber, wherein the mainframe is provided with an oil feed hole connected to a discharge end ofthe oil feed passage.
 5. The scroll compressor of claim 4, wherein theoil feed hole comprises: a vertical hole which is connected to the backpressure chamber and is parallel to a drive shaft of the drive motor;and a horizontal hole which is formed perpendicular to the vertical holeand is connected to the discharge end of the oil feed passage.
 6. Thescroll compressor of claim 1, wherein, when the drive motor is rotatedat a low speed, the flow control valve increases an amount of oilpassing through the oil feed passage so that a back pressure of the backpressure chamber is a value between the suction pressure and thedischarge pressure.
 7. The scroll compressor of claim 1, wherein, whenthe discharge pressure of the scroll compressor is maximum, the flowcontrol valve cuts off the oil feed passage.
 8. A scroll compressorwhich comprises a casing, a drive motor accommodated in the casing, anorbiting scroll to be rotated by the drive motor, a fixed scroll engagedwith the orbiting scroll, a back pressure chamber proximate to theorbiting scroll, an inlet pipe that is disposed in the casing andsupplies refrigerant to a compression chamber formed by the orbitingscroll and the fixed scroll, a discharge pipe that is disposed in thecasing and discharges the refrigerant discharged from the compressionchamber outside the casing, and an oil separator that is connected tothe discharge pipe, and separates and collects oil from the dischargedrefrigerant, the scroll compressor comprising: an oil feed passageconfigured to connect the oil separator and the back pressure chamber sothat oil collected in the oil separator is supplied to the back pressurechamber; and a flow control valve disposed in the oil feed passage, theflow control valve configured to control an amount of oil to be suppliedto the back pressure chamber via the oil feed passage, wherein the flowcontrol valve controls the amount of oil to be supplied via the oil feedpassage in accordance with a suction pressure of the refrigerant to besucked through the inlet pipe, a discharge pressure of the refrigerantto be discharged through the discharge pipe, and a rotational velocityof the drive motor.
 9. The scroll compressor of claim 8, wherein theflow control valve is configured to control an opening area of the oilfeed passage.
 10. The scroll compressor of claim 8, wherein the scrollcompressor is disposed in an outdoor unit of an air conditioner, and theflow control valve is controlled by a controller of the air conditioner.11. The scroll compressor of claim 8, further comprising: a main frameconfigured to support the orbiting scroll and provided with the backpressure chamber, wherein the main frame is provided with an oil feedhole connected to a discharge end of the oil feed passage.
 12. Thescroll compressor of claim 11, wherein the oil feed hole comprises: avertical hole which is connected to the back pressure chamber and isparallel to a drive shaft of the drive motor; and a horizontal holewhich is formed perpendicular to the vertical hole and is connected tothe discharge end of the oil feed passage.
 13. The scroll compressor ofclaim 8, wherein, when the drive motor is rotated at a low speed, theflow control valve increases an amount of oil passing through the oilfeed passage so that a back pressure of the back pressure chamber is avalue between the suction pressure and the discharge pressure.
 14. Thescroll compressor of claim 8, wherein, when the discharge pressure ofthe scroll compressor is maximum, the flow control valve cuts off theoil feed passage.
 15. A scroll compressor which comprises a casing, adrive motor accommodated in the casing, an orbiting scroll to be rotatedby the drive motor, a fixed scroll engaged with the orbiting scroll, aback pressure chamber proximate to the orbiting scroll, an inlet pipethat is disposed in the casing and supplies refrigerant to a compressionchamber formed by the orbiting scroll and the fixed scroll, and adischarge pipe that is disposed in the casing and discharges therefrigerant discharged from the compression chamber outside the casing,the scroll compressor comprising: an oil feed passage configured toconnect the compression chamber and an oil storage tank provided in thecasing so that oil of the oil storage tank is supplied to thecompression chamber; and a flow control valve disposed in the oil feedpassage, the flow control valve configured to control an amount of oilto be supplied to the compression chamber via the oil feed passage,wherein the flow control valve controls the amount of oil to be suppliedvia the oil feed passage in accordance with a suction pressure of therefrigerant to be sucked through the inlet pipe, a discharge pressure ofthe refrigerant to be discharged through the discharge pipe, and arotational velocity of the drive motor.
 16. The scroll compressor ofclaim 15, wherein the fixed scroll comprises an auxiliary oil feed holeconnecting the compression chamber and a discharge end of the oil feedpassage.
 17. The scroll compressor of claim 15, wherein the scrollcompressor is disposed in an outdoor unit of an air conditioner, and theflow control valve is controlled by a controller of the air conditioner.18. The scroll compressor of claim 15, wherein, when the drive motor isrotated at a low speed, the flow control valve increases an amount ofoil passing through the oil feed passage.
 19. A scroll compressor whichcomprises a casing, a drive motor accommodated in the casing, anorbiting scroll to be rotated by the drive motor, a fixed scroll engagedwith the orbiting scroll, a back pressure chamber proximate to theorbiting scroll, an inlet pipe that is disposed in the casing andsupplies refrigerant to a compression chamber formed by the orbitingscroll and the fixed scroll, a discharge pipe that is disposed in thecasing and discharges the refrigerant discharged from the compressionchamber outside the casing, and a vapor refrigerant injection pipe, thescroll compressor comprising: an oil feed passage configured to connectan oil storage tank provided in the casing and the vapor refrigerantinjection pipe so that oil in the oil storage tank is supplied to thecompression chamber through the vapor refrigerant injection pipe; and aflow control valve disposed in the oil feed passage, the flow controlvalve configured to control an amount of oil to be supplied to the vaporrefrigerant injection pipe via the oil feed passage, wherein the flowcontrol valve controls the amount of oil to be supplied via the oil feedpassage in accordance with a suction pressure of the refrigerant to besucked through the inlet pipe, a discharge pressure of the refrigerantto be discharged through the discharge pipe, and a rotational velocityof the drive motor.
 20. An air conditioner comprising: an outdoor unitin which a scroll compressor is disposed; and a controller configured tocontrol the scroll compressor in accordance with set conditions, whereinthe scroll compressor comprises a casing, a drive motor accommodated inthe casing, an orbiting scroll to be rotated by the drive motor, a fixedscroll engaged with the orbiting scroll, a back pressure chamberproximate to the orbiting scroll, an inlet pipe that is disposed in thecasing and supplies refrigerant to a compression chamber formed by theorbiting scroll and the fixed scroll, and a discharge pipe that isdisposed in the casing and discharges the refrigerant discharged fromthe compression chamber outside the casing, wherein the scrollcompressor comprises, an oil feed passage configured to connect the backpressure chamber and an oil storage tank provided in the casing so thatoil of the oil storage tank is supplied to the back pressure chamber;and a flow control valve disposed in the oil feed passage, the flowcontrol valve configured to control an amount of oil to be supplied tothe back pressure chamber via the oil feed passage, and wherein the flowcontrol valve controls the amount of oil to be supplied via the oil feedpassage in accordance with a suction pressure of the refrigerant to besucked through the inlet pipe, a discharge pressure of the refrigerantto be discharged through the discharge pipe, and a rotational velocityof the drive motor.
 21. A scroll compressor, comprising: a fixed scrollof the scroll compressor engaged with an orbiting scroll; a backpressure chamber proximate to the orbiting scroll and connected to anoil source by an oil feed passage so that oil is supplied to the backpressure chamber; a flow control valve disposed in the oil feed passageand configured to control an amount of oil to be supplied to the backpressure chamber via the oil feed passage in accordance with a suctionpressure of refrigerant to be sucked through an inlet pipe, a dischargepressure of the refrigerant to be discharged through a discharge pipe,and a rotational velocity of a drive motor that rotates the orbitingscroll.
 22. The scroll compressor of claim 21, wherein the flow controlvalve is configured to control the amount of oil to be supplied to theback pressure chamber.
 23. The scroll compressor of claim 21, whereinthe scroll compressor is disposed in an air conditioner, and the flowcontrol valve is controlled by a controller of the air conditioner. 24.The scroll compressor of claim 21, wherein, the flow control valvemaintains a back pressure of the back pressure chamber between thesuction pressure and the discharge pressure when the drive motor isrotated at a low speed.
 25. The scroll compressor of claim 21, wherein,the flow control valve cuts off the oil feed passage when the dischargepressure of the scroll compressor reaches a maximum.
 26. The scrollcompressor of claim 21, wherein the flow control valve is configured tosupply oil to the back pressure chamber via the oil feed passage when aratio of the discharge pressure to the suction pressure is 2 or less andthe rotational velocity of the drive motor is 30 revolutions per secondor less.
 27. The scroll compressor of claim 21, wherein, the flowcontrol valve comprises an electronic proportional solenoid valve. 28.An air conditioner having a scroll compressor, comprising: a fixedscroll of the scroll compressor engaged with an orbiting scroll; a backpressure chamber proximate to the orbiting scroll and connected to anoil source by an oil feed passage so that oil is supplied to the backpressure chamber; a flow control valve disposed in the oil feed passageand configured to control an amount of oil to be supplied to the backpressure chamber via the oil feed passage in accordance with a suctionpressure of refrigerant to be sucked through an inlet pipe, a dischargepressure of the refrigerant to be discharged through a discharge pipe,and a rotational velocity of a drive motor that rotates the orbitingscroll.